The present invention relates generally to watchcases and more particularly to watchcases constructed to permit rapid removal and replacement of the bezel to the case body.
FIG. 1 shows a conventional fluidtight watchcase construction comprised of a case body 1' to the back of which is connected a back cover 4' and to the front of which is connected a glass 5' via a round bezel 6'. A watch movement 7' is mounted inside the watchcase. A sealing gasket 8' provides a fluidtight seal between the back cover and the case body. In like fashion, a fluidtight sealing gasket 28' is disposed between an upper inner step of the bezel 6' and the outer periphery of the glass 5', and another fluidtight sealing gasket 18' is disposed between the outer periphery of a lower step of the bezel 6' and an upper inner step of the case body 1' in order to fix the glass 5' and the bezel 6' to the case body 1' in a fluidtight manner. The gaskets 8', 18' and 28' are typically formed of plastic.
Although this prior art structure is exceedingly simple and possesses good fluidtight characteristics, it does suffer several drawbacks. For instance, a bezel of round shape can be easily manufactured by lathing and for this reason round bezels are in widespread use. However, in the case of a non-round bezel, it is difficult to obtain a fluidtight construction due to the difficulty in achieving accurately machined parts of non-round shape and due to the partial deformation of the bezel caused by press and mill workings which are necessary to obtain the non-round shape.
The most important consideration for manufacturing fluidtight watchcases having non-round bezels is to fix the bezel to the case body without deterioration or loss of the fluidtight function. If a rubber gasket is employed for the fluidtight sealing gasket, the fluidtight function is assured but the bezel cannot be satisfactorily fixed to the case body. On the other hand, if a plastic gasket is employed to fix the bezel, the bezel can be adequately fixed but the fluidtight function is deteriorated due to deformation of the bezel and the case body which occurs during removal and replacement of the bezel from the case body, particularly when the parts are thinly made.